Process of producing retorts.



- composed, destroying them.

'oresj containing such a of precious metals,

M. ED ST Aj'li-fENT -rrIcE.;

BENJAMIN SADTLER, or DENYER, COLORADO, AssIenonjroinLBERr G.

"CLARK, OF CINCINNATI, OHIO;

PROCESS or PRODUCING'RETQRT;S."

SPECIFICATION forming part of Letters Patent No. 642,723,

dated February 6,

l cation filedOctober 6,1899. serene. 732,827. on specimens.)

. The especial object of my invention is to produce retorts, the linings for furnaces, and the covering for bricks and other refractory articles adapted for use in the distillation of percentage of zinc as to prevent their economical treatment in ordinary precious-metal-smelting furnaces and such-a percentage of oxid of iron or other corrosive bases as 'to prevent theireconomieal treatment in the retorts of ordinary zinc-distilling furnaces and also to provide such articles for use in other places where refractory materials are required. Valuable quantities such as gold and silver, are often contained in ores of this character; but the ironoxid, &c., excludes their reduction by the means used in zinc distillation,-

since the iron oxid when exposed to the heat required for such distillation slags with and corrodes the fire-clay of which'the retor ts are If, on'the other hand, an "effort' be made to trat the zincbearing ore in the blast-furnace used for the smelting of ores carrying precious metals, the

zinc being vaporized and encountering the air-blast is precipi'tatedas a crust upon the walls of the furnace, obstructing, andfinally stopping the operation of the furnace. In consequence of the above-named conditions there are large q nantities of such ores containing gold and silver and other metals having both iron oxid and zinc (each valuable, if separated) which it has been impossible to economically work either by zinc distillation or by blast-furnace smelting and whicli,therefore, have remained as waste. I have discovered that by applying before burning to the interior and exposed surface of the fire-'clay'retorts comgradually choking it,

monly used in zinc distillation a smearing or coating of a sintering material, such as a silicate of soda or equivalent substance, and covering the same with aflcoating of basic 'material preferably having also on its adjawithit a small per{ cent surface or mixed cent-age of said sintering material and then subjecting the entire kiln or zinc-furnace under a heat of such intensity and material with the adjacent fire-clay, on the one hand, and basic material, on the other,

body to a' firing in a duration as to fuse the sintering I can, through the chemical'affinity ofthe" sintering material for each of these substances, respectively, so interlock this lining or coating of basic material to the fire-clay body of the retort as to produce a practicallysolid cohering retort capable of sustaining the heat to which it is exposed in use and impervious to the oxid of ironor other corrodj ing ingredients of the ores to be treated. The

silicate of soda when subjected to the heat above mentioned, cate of alumina of the body of the retort-and the basic material with which it is-also'in con-,

tact, forms a chemical union between the fire clay of the retort, on the one hand-,1 and .the magnesia orother basic material composing the lining or coating,on the other hand,there-- by sintering together or binding the substances constituting the body and'the lining I or coating, respectively,and a surface of basic material is produced capable of withstanding the action of the oxids of ironor other chemical' agents in the ores at the heatvof distillain connection'with'the silition of the zinc oreand, which is also capable r of resisting theabrasion from the ores and tools used .upon it, to which the surface of such retorts is necessarily exposed. The sintering material serves, further, by its chem-' ical reaction to lock together and give subposing the lining or coating, Suppose, for instance, the basic material to be magnesia in the form of calcined maguesite, and-a solution of silicate of sodium (which is a thick gummy liquid) is smeared on the inner-sur-- faceof the. fire-clay body. Then, while a volving the circular retort, let this basic material be thrown in the form of a powder into) stantialcoherence to'the basic materials comthe retort, The silicate of sodium, as the wa-s would scale off, since these materials make no chemical combination .at ordinary. temperatures. The retort so preparedis now heated, as before described,lto a temperature action in the materials here mentioned is as follows: The exteriorof the individual particles of magnesia become converted into a silicate of sodium and magnesium,-'which at high heat become viscid or semif used, making the exteriorof these grains sticky or gummy.

' 'lhey consequently adhere to each other and to the body of the retort,formiug a'strong and compact lining, theparticles of which are I bound together by this film of silicate of sodium and magnesium, but the interior of which remains magnesia and is essentially and strongly basic. \Vhen these double silicates complete their chemical saturation, they solidify or set. Care should be taken in this operation to limit the amount of silicate of sodium (or other sintering material) used, as the fusibility of compounds of sodium would, if used in too large quantity, produce a condition of fluidity. This fluidity, if carried to excess, would start an intcrmingling of the basic particles of the lining and the acid particles of the retort, tending to destroy the retort or, at least, its refractory quality. Basic materials having little or no chemical afiinity for water are preferable. If the basic lining were applied to the fire-clay retort without this process of sintering the substances together, it would be practically incapable of resisting the abrasions to which such retorts treating such ores are necessarily subjected and would not have the sameca pacity to resist the action of iron oxide. I prefer to apply the silicate of. soda or other substance having the necessary chemical affinity as a wash or thin coating t6 the inner surface of the dried but unburnt fire-clay of the retort, then allow it to soak in somewhat before applying the basic material, and to mix a small percentage of the sintering material with the basic lining before or when applying it to the surface thus washed or coated; but the essential considerations are to insure the presence of the sintei-ingmaterial on the line of juncture between the fire-clay body and basic lining or coating and the subsequent firing, wherebythe desired interpenetration and chemical bond is secured. I prefer to use the basic material pulverized to about the degree of fineness correspondingto a mesh of twenty to an inch and to re jectl the fine dust which tendsto absorb. an

'und ue quantity of sintering material. Icompose the fire-clay body of the ordinary fireclay mixture, molding it into' the shapeof a retort, generally about four feet long and about eight inches internal diameter, and about one inch in thickness. Itis then dried, either by the usual air drying process or by the sintering material and the basiclining. I steam process, or by-both, before applying the commonly use a coating of sinterin g material.

about one thirty-second of an inch in thickness, which becomes considerably less when the chemical combination takes place as the result of firing. I have found oneeighth of an inch thickness of basic material to give entirely satisfactory results, and have sometimes made it uniform througlibut the surface of the retort and sometimes somewhat thicker at the bottom, obtaining satisfactory results in each case. I treat in the same manner the outer top surface of the retorts, since when one of the series of retorts is broken during the operation the hot ore falling upon the retort below would be liable to destroyit', if not thus shielded.

I have found that a heat of about 1,500 Fahrenheit continued for two or three days is desirable for the firing after the materials.

above mentioned are brought together, and a higher degree of heat or longer time may be used to advantage. Less perfect results may be obtained where less heat is used or the duration of firing shortened. It is desirable to have the basic material-at least an eighth of an inch thick. It may be composed of dolomite, magnesia, titanic iron ore, corundum, or other refractory and infusible basic materials, or two or more of such materials mixed. The sintering material should be a small percentage, not more than from ten per cent. to twenty per cent. of the entire linin While this process is particularly adapted for use in zinc retorts and other articles adapted to be used in zinc distillation, it is manifest that it may be used for the production-furnaces, fire-brick and other refractory material, in any location where such articles are used without departing from myinvention.

I claim- 1. The herein-described process of manufacturing retorts, consisting of applying to the surface of the fire-clay body a sintering material capable of forming under heat a chemical bond with the adjacent fire-clay and also witha basic material, applying to such sintering material a coating or lining of basic material capable of forming under heat a chemical bond therewith, and thereupon sub IIC mg the composite resultant toheat suiti- I I to effect a chemical union between such s tering material and adjacent portions of g. the clay. body and between the sintering ma- 5 terial and particles of the b sic lining, respectively, substantially as an for the purpose described.

2. The herein-described process of manufacturing refractory articles-consisting of apxo plying to the surface of the fire-clay body a.

coating of sintering material, and-then a coat-.' ing of basic material and subjecting the whole to heat suflicient to fuse such sintering mate-- rial into said body and into the basic lining :3 whereby said body and lining are secured todescribed.

3. The herein-describedprocess of manuplying to the surface-of the fire-clay body'a coating of silicate of soda, then' a coating of said body and into said basic lining, whereby stantia1ly as described.

BENJAMIN SADTLER. Witnesses:

ALBERT G. CLARK, MARGARET SINCLAIR.

gethei' by a chemical bond, substantially as facturing refractory articles consisting of apbasic material-and subjecting the whole to a heat sufficient to fuse said silicate'of sodainto body and lining are secured together, sub-.2

Correction inLtters. Patent No. 642,723.

v It is hereby certified that in;]' tters Patent No. 642,723, granted Febrnary 6, 1900,

npon the application of Benjamin Sadtler, of Denver, Colorado, for an improvement in Processes of Producing Retorts, an error appears in the printed speeification reqn irin-g correction asnfol lowsz On page 2, line 84, the clause steam process, or' by both, before applying the, should be stricken out an( l inserted after line 83', same page; and that the said Letters Patent should be read with this" correction therein that the same may conform to the record of the case in the Patent Office.

' Signed, counter-signed, ahd sealed this 20th day ofFebruary, A. 1)., 1900.

[SEAL] THOS. RYAN,

First Assistant Secretary of the Interior. Counter-signed C. H. DUELL,.

Commissioner of Patents. 

